Tap holder



1 Patented Feb. 17, 1931 7 mcnmntreon coMBAnY, A; CORPORATIQNgeOF M'ASSAGI IUSETTS I TAP HOLDER' Application filed I April 19,

j "This invention relatesto a tap holder for drillingmachines, multiple tappers, multiple "d ril ling macl'iinesg lathes and si r nilar apparatus for tapping screwthreads in holes. In t 5 tappingholes; threads of 'various leads orpitehes, as is done in; multiple'tapping machines, thehaving threads of? greater pitch orlead must advancemore rapidly into I the holeand thusbe drawnahead of the other i 10 taps having lesser'leads If a number of taps of different leads are'di'iven; from'a common source, it is'necessarythat the tap holders move-"forwardly'at proportionately varying a mites, lvloreoven'indrill ing blind holes, those taps having the greater leadwill' reach the bottomof the hole quicker'than the taps having lesser leadsand may-thereby bebroken- "unless their forward driving movement be stopped upon reaching the bottom of the hole.

An object of my invention is to provide at tap holder'that may 'movelongitudinfall'y ont'he driving-spindle and thus advance independently of the spindle.

Another object of the invention is 'toprovide a tap holderhaving a positivedrive which slips to prevent the tap from breaking, "in the'event that the tap reaches or strikes the bottom of a blindhole and is thereby stopped from further movement while the driving spindle continues to'rotate,

Further ob ectsand features of the invention are to provide a' new and improved tap holding collet which the tap may be securely held and released by a short}, simple ''inovem'ent of the collet; to provide a tap gholding 3 mechanism that is normally held eb'aiikwardly on the driving spindle but which may float forwardly thereof under tension;

1 and to provide a tap holding mechanism havillustrated inthe accompanying drawings;

wlii'chp s ,7 Flg. 1 is a longitudinal side viewof a tap holder and tap, embodying the preferred form 1 of the inventionl' Fig. 2 is a longitudinal sectionalview; of the tap holdertaken on line 2'2 ofgFig; 3.

" Louis smnumnx, or-srmnemnnn, MASSACHUSETTS, Assienon 'ronnusn Fig. 3 is a longitudinalsectionalview taken at right angles to thesection 'of Fig, 2, on the.

Fig. 4L is across sectional view taken-011 line ofFig. 2, and: g line 55 of Fig. 3. 1 g

In my present invention, the tap holding means is so carried on adriving spindle that it may float or slid'e'forwardly thereon' 'while being rotated. The rotational driving move- Fig; v5 is a, cross sectional view taken on ment is transmittedfrom' the spindle to a driving key which is freely slidahle longitudinally ofthe spindle, and from thence the transmitting element which is keyed to the -1novement is imparted to connecting or f tap; securing elements The connecting or transmitting element is pressedagainst' the driving key and is providedat its'end with a suitablev groove in which the edgejof the driving key is received so that the tap is driven from the key. Y 7 p Thetransmitting element is free to move longitudinally of the. driving key of thevtap holding elements, and is held into. engagement with aisplit'friction spring whichyin the event that the tap reaches the-bottom i of ablind hole, expands, and permits the connecting element to move out of engagement with the driving: key and thus disconnects the tap from, a direct. driving relation to the driving spindle.

R-eferring more particularly to the accompanying drawings, the tap holding means is,

provided with a spindle 10, which has .a lindricalportion 11 entering, a holding sleeve or housing 12, and .a'tapered, projecting end p portion 13 adapted to be inserted in thedrive ing element of the drilling orsimilarinm chinei The end of the spindle within the sleeve or housing 12 is enlarged as at 14 to fit the inner surface of the'sleeve, and is cleft T or bifurcated to receive a longitudinally fiattened driving key 15 extending transversely through the sleeve 12. The sleeve 12 is provided, at one end, with an inturned flange 16 which serves to retain a spring 17 encircling the cylindrical portion 11 of the spindle and confined between the flange 16 and the projecting enlarged portion 14 of the spindle. The spring 17 serves to press or bias the sleeve 12 backwardly towards the taper element 19,"one end ofwhich is provided with an inwardly projecting retaining shoulder 19a engaging the collet 18, and the other end of which encircles a reduced portion of the sleeve 12 and is held thereon by the projecting ends of the key 15.

The tap collet 18 is provided at its forward end with a longitudinal hole20 of a diameter to fit the tap and havin a squared portion 21 to prevent the tap from rotating therein. Atthe inner or rear end of the tap holding collet 18, there is provided aetransverse recess or key-way 22, in which is received a forwardly projecting'key portion 23 of a transmitting element 24. The rear end portion of the transmitting element 24. closely fits the forward end of the sleeve 12,. and

is provided with a rounded recess 25 into which fits the roundedend of the transverse driving key 15. The transmitting element 2 1 is slidable within the sleeve 12, but pressed tightly against the forward edge of the transverse key 15 by means of: a split ring 26, one edge of which rests against the rear or inner end of the tap collet 18 and contracts about a friction cone surface 26a on the transmitting element 2 1. A tap 27 having a stem adapted to fit in the opening 20, may be inserted and held in the tap holding collet 18 by any suitablemeans.

In the preferred form of the invention, the tap is preferably held .in-thecollet by means of a ball 28 positioned-in a transverse socket 29 in thecollet 18. The ball 28 is of some what greater diameter than the thickness of the wall'of the collet 18 and is held inwardly to project into a suitablenotch or groove in the stem of the tap 27 by means of a tap chuck or ring 30 encircling the tap collet.

The tap chuck or ring 30 is retained on p the collet by means of a screw 31 which projects into an arcuate groove 32 inlthe circumference of the collet. A springi33encircling the collet 18 is mounted in a recess 34 at the rear edge of the chuck 30, and is secured atone end .to the collet and at the turning the chuck counterclockwise on the collet to the limitof movement of the screw 31 in the groove 32, a depression 34a in the inner surface of the chuck is brought into alignment with the ball recess 29, permitting the ball to move outwardly and releasing the stem of the tap so that it may bewithdrawn.

When thetap is mounted and secured in the collet 18 and the spindle 13 is positioned in the driving part of a machine, the tap is started in a hole to be tapped. If the tap has a greater pitch or lead than that at which the spindle is advanced, it will draw the collet 18 forwardly relative to the spindle and will, accordingly, draw forwardly the sleeve 12 and the driving key 15. The sleeve '12 will thenfioat forwardly on the spindle 13, compressing the spring 17. The spindle.

13'will, still continue to drive the key 15 which is of s'uificientwidth to remain in engagement with the fork end portion 14 of the spindle throughout the forward floating of the tap retaining collet. The key 15 remains :pands under pressure until the key 15 is free of the notched end of the transmitting element! Thereafter, the spindle 13 continues-to rotateijwithoutdriving the tap collet and tap.

To remove the key 15' and stop the sleeve elements and spindle, the spindle is drawn outwardly against the pressure of the spring 17 and the key 15- is driven transversely of the sleeve in the direction of the arrow in Fig.2.

By means of the above tap holder, a number of taps of different'leads may be mounted in'a multiple drilling or tap machine and all .drivensimultaneously from a common driving source. Thus,taps having the greater leads will alvance more rapidly into the work independently of taps of lesser leads. The invention thereby provides a. very simple and effective way of. driving a number of'taps of different leads. w e

i As changes of construction could be made within the scope of my invention, it is intended that allmatter'contained in the above description or shown in the-accompanying drawings shall be interpreted as lllustrative and not m a limiting sense.

Having now described my invention, what I claim as 'new'a'nd desire to secure by Let ters Patent is: j

1. A tap'holder which comprises a sleeve, a driving key in said sleeve, a spindle extending into said sleeve and engaging-said surface to yieldingly hold said connecting thereof, a tap holding means mounted in sald sleeve, and couplmg means engaging and slidable longitudinally of said holding 7 means and biased into engagement with said ma transverse longitudinally flattened key in.

driving key. V y

2. ,A tap holder which comprises asleeve,

said sleeve, a projecting driving spindle slidably mounted in said sleeve and bifurcated to slidably engage said key, a spring biasing said spindle towards said key, a tap holding means mounted in said sleeve, a connecting member having a longitudinal slidable engagement with said tap holding means and notched to engage the edge of said driving key, and means yieldingly holding said connecting member against the edge of said driving key. 7

3. A tap holder which comprises a sleeve, a transverse longitudinally flattened key in said sleeve, a projecting driving spindle slidably mounted in said sleeve and bifurcated to slidably engage said key, a spring biasdriving key and slidable longitudinally member into engagement with said key.

I In testimony whereof, I have hereunto signed my name. 1

BERNARD LOUIS SMEUNINX.

ing said spindle towards said key, a tap holding means mounted in said sleeve, a 7 connecting member havmg a longitudinal slidable engagement with said tap holder and notched to engage the edge of said driving key, sald connecting member having a cone friction surface, and a split friction ring contracted about said cone surface to v yieldingly hold said connecting member into 5 engagement with said key.

' 4. A tap holder which comprises a. sleeve,

a transverse longitudinally flattened key in said sleeve, a projecting driving spindle slidably mounted in said sleeve and bifurcated to slidably engage said key, a spring biasing said spindle towards said key, a tap holding means mounted in said sleeve, and

' yieldable means for driving said tap holding. means from said transverse key.

5. A tap holder which comprises a driving key, a tap holding means, a connecting member between said driving key and said 7 holder having alongitudinally slidable radially fixed engagement with said tap hold-' er and notched to engage the edge of said driving key, and a spring yieldingly holding said connecting member against the edge of said driving key, the surfaces of said notch and said key imparting a longitudinal thrust against said spring when said key is rotated to drive said connecting member.

,6. A device of the type'described, which comprises a tap holding means, a driving. key transverse to the axis of said tap holding means, a connecting member having a longitudinally slidable engagement with said tap holder and notched to engage the V edge of said driving key, said connecting member having a conical surface and a split spr ng rmg contracted about said conical 

